Sewing machine looper mechanism



A. B. CLAYTON SEWING MACHINE LOOPER MECHANSM Filed Oct. 29, 1951 IIIL May 2, wsa

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Patented May 2, 1933 UNTED ANDREW B. CLAYTON, OF UNION, NEW JERSEY, ASSIGNOR '3.10 THE SNGER MANUFAC- TURING COMPANY, OF ELIZABETH, NEW JERSEY, A COREGRATION OF NEW' JERSEY lm i Cil,

SEWING MACHINE LOOPER MECHANISIVI Application led October 29, 1931.

This invention relates to sewing machines more particularly of the chain-stitch type having a thread-carrying looper which cooperates with a reciprocating needle to produce the well known two-thread chain-stitch.

The invention has for an object to provide an improved looper-actuating mechanism adapted more particularly for cylinder-bed sewing machines in which the work is fed across the cylinder and across or transverse to the blade of the looper. Another object of the invention is to provide for the manual retraction of the looper to a position facilitating the threading of the same; the threadeye at the free end of the looper' being retractible well beyond the edge of the sewing machine throat-plate so that the under thread may be easily inserted therein.

1With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and ai'- rangements of parts hereinafter set forth and illustrated in the accompanying drawing of a preferred embodiment of the invention from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art. v

Fig. 1 of the drawing is a longitudinal vertical section through the cylinder-bed of a sewing machine embodying the invention. Fig. 2 is a transverse vertical section through the cylinder-hed showing the looper mecha- 4nisni and the manually operated looper-re- '-tracting rock-shaft journaled in the sewing machine standard. Fig. 3 is a view of certain elements of the looper-actuating linkage in the two extreme positions attained :during each stitch-forming cycle while the fio machine is in normal sewing operation. Fig. 4 is a perspective view of one of the rockerarms of the looper-driving mechanism. Fig. 5 is an elevation of the primary looper-actuating pitman. Fig. 6 is an elevation of the manually operated lever which is mounted upon and exteriorly to the sewing' machine standard for retraction of the looper to threading position. Fig. 7 is a section on the line 7 7, Fig. 2, and Fig. 8 is a perspective view of the lever yshown in Fig. 6.

Serial No. 571,703.

The frame of the machine includes the usual hollow standard 1 and hollow cylinderloed 2. The main-shaft 3 extends within and longitudinally of the cylinder-bed 2. rihe machine has the usual reciprocating needlebar 4 carrying the needles 5. it also has the usual throat-plate 34 and feed-dog 7 arranged to feed bed 2.

Cooperating with the needles 5 is the thread-carrying looper 8 which is mounted on the looper-carrier 9 fulcrumed on the pin 10 carried by the head-block 11 of the loopersupporting rock-shaft 12 journaled in the cylinder-bed 2 and oscillated by the forkconnection 13 with the eccentric 14 on the main-shaft; this connection imparting the usual side-throw or needle-avoiding movements to the looper 8.

The looper-carrier 9 has a ball-stud 15 which is connected by the long linlr 16 to the ball-stud 17 on the rocker-arm 18 fulcrumed on the cross-pin 19 in the cylinder-bed 2. The rocker-arm 18 is connected by a short link 2O to a second rocker-arm 21 which is clamped to the sleeve 22 journaled to rock on the intermediate eccentric portion 23 of a manually operated rock-shaft 24, 24 journaled in the alined bearings 25, 25 in the standard 1. There is fixed to the rock-shaft section 24 a handle 26 by means of which the intermediate eccentric lportion 23 may be rocked from full line to dotted line position, Fig. 1, corresponding to a shift of the handle 26 from full line to dotted line position, Fig. 6. rlhe sleeve 22 carries a ball-ended arm 27 which is connected by the pitman 28 to thel crank-strap 29 embracing the crank 30 on the main-shaft 3.

' When the parts are in normal operative or sewing relation, the handle 26 is in full line position, Fig. 6, and the eccentric portion 23 of the manually operated rock-shaft 24. is in full line position, Figs. 1 and 3. YVhile the machine is in sewing operation, the rockerarms 21 and 18 oscillate between the eXtreme positions shown in Fig. 3 and it will be observed that the link 2Q and rocker-arm 21 constitute a toggle-device and approach alinement in the dotted line position of the the work across the cylinderparts, Fig. 3, when the looper 8 is at the end of its loop-seizing or advancing stroke. This approach to alinement of the link 20 and rocker-arm 21 slows up the advancing movement of the looper after the latter has seized the needle-loops and enables a comparatwely short-stroke looper to be used while retaining a rapid loop-seizing and loop-shedding action. The rock-shaft 9A is detained in its normal sewing position by the spring-pressed detent 31 the conical ended head 32 of which enters a V-shaped groove 33 in the rockshaft 211.

When it is desired to thread the looper, the machine is stopped with the looper in retracted position, as shown in full lines, Fig. 1. The operator then shifts the handle 26 from full to dotted line position, Fig. 6, thereby rocking the shaft 24, 24E and shifting the intermediate eccentric portion 23 to dotted line position, Fig. 1. This manually operated movement of the eccentric 23 causes the rocker-arms 21, 18 and link 20 to move to dotted line position, Fig. 1, thereby retracting the looper 8 to dotted line position wherein the looper-eye 8 is carried well out from under the throat-plate 34E and is readily accessible for threading purposes. During this manual shift of the parts the link 2O and rocker-arm 18 approach alinement and constitute a second and reversely acting toggle-device which has the effect of increasing the retracting movement imparted to the link 16 and looper-carrier 9, as is desirable to carry the looper-eye 8 well to one side and out from under the throat-plate. After the looper has been threaded the handle is returned to fnll line position, Fig. 6, and the parts shown in dotted lines in Fig. 1 are 'returned to their full line or normal sewing positions. The inner face of the handle 26 is provided with an undercut arcuate slot 35 which is entered by the screw-pin or stop 36 projecting from th'e standard 1.

Having thus set forth the nature of the invention, what I claim herein is 1. Looper mechanism for sewing machines having, in combination, a thread-carrying looper, driving means for imparting advancing and retracting movements to said looper in the formation of stitches, manually operated means for retracting the looper to a position facilitating threading thereof, said driving and manually operated means including a pair of rocker-arms and a link connecting said arms, said link and rocker-arms being so relatively related that said link approaches alinement with one of said rocker-arms during each stitch-forming cycle as the looper approaches the end of its advancing stroke, and approaches alinement with the other rockerarm during the manual retraction of the looper to threading position.

2. Looper mechanism for sewing machines having, in combination, a thread-carrying looper, means for imparting loop-seizing movements to said looper, said means including a toggle-device for slowing up the motion of said looper as it nears the end of its loopseizing stroke, and manually operated means for retracting said looper to a position for convenience in threading, said means including another toggle-device for increasing the retracting motion manually imparted to the looper, said toggle-devices having a link in common.

3. In a sewing machine, the combination with a reciprocating needle and a main-shaft, of a looper, means for imparting side-throw movements to said looper, and means for imparting loop-seizing and -shedding movements to said looper, said last mentioned means including a rocker-arm spaced from said looper, a link-connection between said rocker-arm and looper, a second rocker-arm, a manually operated eccentric fulcrum support therefor, a link-connection between said rocker-arms, a crank on said main-shaft, and a pitman connection between said crank and second-mentioned rocker-arm.

4. In a sewing machine, a frame including a supporting standard and a hollow cylinderbed, a reciprocating needle, a main-shaft, a 'thread-carrying looper-blade mounted with-- in the free end of said cylinder-bed and having endwise advancing-and-retracting loopseizing and -shedding movements lengthwise of the cylinder-bed, means connected to the main-shaft within said standard for imparting said loop-seizing and -shedding movements to the looper-blade and manually operated means mounted in and accessible exteriorlylof said standard for retracting said looper-blade lengthwise of itself and toward said standard and beyond its normal operative retracted position in sewing, for convenience in threading.

In testimony whereof I have signed my name to this specification.

ANDREV B. CLAYTON. 

